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    Trees that last

    Trees that last: Plant the forest, then make sure it grows.

    Forests are still being cleared at 10.9 million hectares a year. Bringing a hectare back costs a median of $1,691, and the hard part is making sure the trees last.

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    Ryan K. Hertel · heyitskenton

    The problem

    What we're up against.

    • Forests, still falling.

      Forests are being cleared at 10.9 million hectares a year, a rate the UN's food agency calls still too high.

    • Much is already gone.

      About 489 million hectares of forest were lost from 1990 to 2025, more than 460 million are degraded, and only 206.5 million are under restoration.

    • Fire, a growing threat.

      Fire caused 42% of the 25.5 million hectares of tree cover lost worldwide in 2025.

    • A goal far from met.

      The Bonn Challenge aims to restore 350 million hectares of degraded and deforested land, and about 210 million have been committed so far.

    • Fewer trees where people have less.

      In US cities, low-income neighborhoods have 15.2% less tree cover on average, and they run hotter.

    What works

    Proven, and ready to grow.

    • Let nature do some of the work.

      In tropical forests, restoration success for biodiversity was 34% to 56% higher where forests regrew naturally than where they were planted, and 215 million hectares of the tropics could regrow on their own.

    • Farmers regreened the Sahel.

      Farmers in Niger have let trees regrow from old stumps and roots across 4.2 million hectares, adding an estimated $17 million to $21 million a year to one region's income.

    • Native forests do more.

      Across studies worldwide, native forests stored carbon, provided water, held soil and supported wildlife better than plantations.

    • Trees and health.

      Where an invasive beetle killed ash trees across America, it was linked to 15,080 more deaths from heart disease and 6,113 more from lung illness.

    • Greener lots, safer streets.

      In a randomized trial with 541 vacant lots in Philadelphia, greening them cut gun violence, crime and fear, and people nearby who felt depressed fell by 41.5%. The greening was mostly grass, with a small number of trees.

    What a family could fund

    Where the money goes furthest.

    • Local groups, funded directly.

      TerraFund, run by the World Resources Institute and partners, backs local African groups restoring land with trees. Applicants asked for an average of $145,000 to restore 200 hectares each, and more than 3,200 groups applied.

    • Regrowth, spread farm to farm.

      World Vision says farmer-managed natural regeneration has regrown over 18 million hectares in over 40 countries.

    • City trees that pay back.

      Researchers estimate that a tree planted in each of Portland's census tracts would bring $14.2 million a year in benefits, against $2,716 to $13,720 a year to care for them.

    • Vacant lots, cheaply.

      Greening a vacant lot costs about $5 a square meter, then about $0.50 a square meter to maintain.

    • Closing the tree gap.

      Closing the tree cover gap in US cities would take about $17.6 billion, benefiting 42 million people in low-income neighborhoods.

    Honest limits

    What money can't promise.

    • Many planted trees die.

      Across restoration sites in tropical and subtropical Asia, 18% of planted trees died within a year, and 44% within five.

    • Big programs can fail.

      Decades of tree planting in northern India didn't increase forest canopy cover, and in Chile, subsidies grew plantations of exotic trees while native forest shrank.

    • Not every place is meant to be forest.

      Across Africa, vast areas of grassland and savanna are threatened by tree planting in the name of restoration.

    • Carbon claims get inflated.

      A widely cited estimate of how much carbon tree planting could store was about five times too large.

    • Few check whether trees survive.

      Only 5% of tree-planting organizations studied mention measuring survival, and in southern Costa Rica, 50% of regrown forest was cleared again within twenty years.

    Hard questions

    Asked and answered.

    1. You might ask

      Isn't planting trees just greenwashing?

      Ryan

      It is when it's sold instead of cutting emissions: even forests across the world's drylands would do little for the climate, a reason to cut emissions fast. The case for trees that last rests on more than carbon, such as farm incomes, and healthier neighborhoods.

    2. You might ask

      Why not let forests regrow on their own?

      Ryan

      Often that's best: natural regrowth does better for wildlife, and costs a median of $513 a hectare. But it works only with seed trees nearby and protection from grazing.

    3. You might ask

      How do you know the trees survive?

      Ryan

      Often nobody checks. An initiative can pay for counts of living trees years later, and satellites can now count single trees: 1.8 billion of them across Africa's Sahara and Sahel.

    In the slider

    See what your fortune could do here.

    Trees that last

    The slider prices this cause with these numbers:

    • Restoring a hectare costs a median of $1,691 across 243 projects worldwide, with up to five years of upkeep.
    • The whole need is the Bonn Challenge's goal: 350 million hectares of degraded and deforested land.
    • A paid-for hectare isn't always a living forest: in tropical Asia, 44% of planted trees were dead within five years.
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    More of the Blueprint

    Keep reading.

    17 more chapters on the way

    Back to Keep 100

    Sources

    Every number in this chapter, and where it came from.

    1. Source 1: Global deforestation slows, but forests remain under pressure, FAO report shows (opens in a new tab)

      Food and Agriculture Organization of the United Nations, 21 October 2025. Checked 16 October 2026.

      On the Global Forest Resources Assessment 2025.

    2. Source 2: The global cost of international commitments on land restoration (Verhoeven and others) (opens in a new tab)

      Land Degradation & Development, 19 August 2024. Checked 16 October 2026.

      Costs from 243 projects worldwide, in 2024 dollars.

    3. Source 3: FAO report: Restoring forests and landscapes is critical to meeting global food security and development goals (opens in a new tab)

      Food and Agriculture Organization of the United Nations, 28 September 2026. Checked 16 October 2026.

      On The State of the World's Forests 2026.

    4. Source 4: Tropical Rainforest Loss Slowed in 2025, but Fire is a Growing Threat to Forests Worldwide (opens in a new tab)

      World Resources Institute, 29 April 2026. Checked 16 October 2026.

      WRI's Global Forest Review, from University of Maryland satellite data.

    5. Source 5: Germany and IUCN celebrate 15 years of the Bonn Challenge, the world's largest restoration initiative (opens in a new tab)

      IUCN, 17 November 2025. Checked 16 October 2026.

    6. Source 6: The tree cover and temperature disparity in US urbanized areas (McDonald and others) (opens in a new tab)

      PLOS ONE, 28 April 2021. Checked 16 October 2026.

      A satellite study of US communities.

    7. Source 7: Ecological restoration success is higher for natural regeneration than for active restoration in tropical forests (Crouzeilles and others) (opens in a new tab)

      Science Advances, 8 November 2017. Checked 16 October 2026.

      A meta-analysis of 133 studies.

    8. Source 8: Global potential for natural regeneration in deforested tropical regions (Williams and others) (opens in a new tab)

      Nature, 30 October 2024. Checked 16 October 2026.

    9. Source 9: Land use change and climate-smart agriculture in the Sahel (Cotillon, Tappan and Reij) (opens in a new tab)

      US Geological Survey, 2021. Checked 16 October 2026.

    10. Source 10: Dry land tree management for improved household livelihoods: farmer managed natural regeneration in Niger (Haglund and others) (opens in a new tab)

      Journal of Environmental Management, 1 April 2011. Checked 16 October 2026.

      A household survey in Niger's Maradi region.

    11. Source 11: The biodiversity and ecosystem service contributions and trade-offs of forest restoration approaches (Hua and others) (opens in a new tab)

      Science, 17 March 2022. Checked 16 October 2026.

      A global synthesis of 264 studies.

    12. Source 12: The relationship between trees and human health: evidence from the spread of the emerald ash borer (Donovan and others) (opens in a new tab)

      American Journal of Preventive Medicine, 1 February 2013. Checked 16 October 2026.

      A natural experiment across fifteen US states; an association, not proof of cause.

    13. Source 13: Citywide cluster randomized trial to restore blighted vacant land and its effects on violence, crime, and fear (Branas and others) (opens in a new tab)

      Proceedings of the National Academy of Sciences, 26 February 2018. Checked 16 October 2026.

      Philadelphia. The greening was mostly grass, with a few trees.

    14. Source 14: Effect of Greening Vacant Land on Mental Health of Community-Dwelling Adults (South and others) (opens in a new tab)

      JAMA Network Open, 6 July 2018. Checked 16 October 2026.

      A randomized trial in Philadelphia.

    15. Source 15: TerraFund for AFR100 (opens in a new tab)

      AFR100. Checked 16 October 2026.

      The program's own account.

    16. Source 16: Farmer Managed Natural Regeneration (opens in a new tab)

      Paris Peace Forum. Checked 16 October 2026.

      World Vision's own account of its project.

    17. Source 17: The association between tree planting and mortality: A natural experiment and cost-benefit analysis (Donovan and others) (opens in a new tab)

      Environment International, 30 October 2022. Checked 16 October 2026.

      Portland, Oregon.

    18. Source 18: Citywide cluster randomized trial to restore blighted vacant land and its effects on violence, crime, and fear (Branas and others), full text (opens in a new tab)

      Proceedings of the National Academy of Sciences, 26 February 2018. Checked 16 October 2026.

    19. Source 19: The road to recovery: a synthesis of outcomes from ecosystem restoration in tropical and sub-tropical Asian forests (Banin and others) (opens in a new tab)

      Philosophical Transactions of the Royal Society B, 14 November 2022. Checked 16 October 2026.

      A synthesis of 176 restoration sites.

    20. Source 20: Limited effects of tree planting on forest canopy cover and rural livelihoods in Northern India (Coleman and others) (opens in a new tab)

      Nature Sustainability, 13 September 2021. Checked 16 October 2026.

    21. Source 21: Impacts of Chilean forest subsidies on forest cover, carbon and biodiversity (Heilmayr and others) (opens in a new tab)

      Nature Sustainability, 22 June 2020. Checked 16 October 2026.

    22. Source 22: Conflation of reforestation with restoration is widespread (Parr and others) (opens in a new tab)

      Science, 15 February 2024. Checked 16 October 2026.

    23. Source 23: Comment on The global tree restoration potential (Veldman and others) (opens in a new tab)

      Science, 1 October 2019. Checked 16 October 2026.

    24. Source 24: People plant trees for utility more often than for biodiversity or carbon (Martin and others) (opens in a new tab)

      Biological Conservation, 1 September 2021. Checked 16 October 2026.

      A study of 174 tree-planting organizations.

    25. Source 25: The ephemerality of secondary forests in southern Costa Rica (Reid and others) (opens in a new tab)

      Conservation Letters, 26 September 2018. Checked 16 October 2026.

    26. Source 26: Limited climate change mitigation potential through forestation of the vast dryland regions (Rohatyn and others) (opens in a new tab)

      Science, 22 September 2022. Checked 16 October 2026.

    27. Source 27: Drivers of farmer-managed natural regeneration in the Sahel (Lohbeck and others) (opens in a new tab)

      Scientific Reports, 14 September 2020. Checked 16 October 2026.

    28. Source 28: An unexpectedly large count of trees in the West African Sahara and Sahel (Brandt and others) (opens in a new tab)

      Nature, 14 October 2020. Checked 16 October 2026.